Use gettext to add subtitle to short titles (use variable for length).

bookwyrm/templatetags/utilities.py

@@ -2,6 +2,7 @@
 import os
 from uuid import uuid4
 from django import template
+from django.utils.translation import gettext_lazy as _
 
 
 register = template.Library()
@@ -20,13 +21,16 @@ def get_user_identifier(user):
 
 
 @register.filter(name="book_title")
-def get_title(book):
+def get_title(book, too_short=6):
     """display the subtitle if the title is short"""
     if not book:
         return ""
     title = book.title
-    if len(title) < 6 and book.subtitle:
-        title = "{:s} ({:s})".format(title, book.subtitle)
+    if len(title) < too_short and book.subtitle:
+        title = _("%(title)s: %(subtitle)s") % {
+            "title": title,
+            "subtitle": book.subtitle
+        }
     return title